I think Steve is assuming the "dorsal fin" is a functional control surface. I was seeing it as a fixed, but removable part of the fuselage, to get at the removable wing....just additional side surface area, the better to knife-edge with?

I don't really buy into the "nose rudder" idea either. If a flat 360 spin is the goal, it's going to spin around the CG. So the control input should be as far from the CG as possible....i.e. at the tail.

I think Steve is assuming the "dorsal fin" is a functional control surface. I was seeing it as a fixed, but removable part of the fuselage, to get at the removable wing....just additional side surface area, the better to knife-edge with?

I don't really buy into the "nose rudder" idea either. If a flat 360 spin is the goal, it's going to spin around the CG. So the control input should be as far from the CG as possible....i.e. at the tail.

(just adding my 2 rand worth.....;-)

The latest sketch shows what looks very much like a hinged surface... my comments pertained to that

Steve

Images

Very good eye, there, Steve. I missed that detail but believe you're correct. Biggest issue I see with a truly flat pirouette type spin is the loss of lift from the wings as airspeed drops and reverses, especially across the wing that is pivoting backwards.

These views got me thinking all kind of weird thoughts.....a probably low performance but visually cool "Fish" with a fairly standard build wing but all-moving tail surfaces built by using monofilament titanium wire for the leading edges and a straight film covering from wire to wire with no structural filler similar to a hang glider wing. They would be light and flexible, very forgiving on ground contact and although the flex factor would probably prevent tight precision flying it just might add a bit of oomph coming out of dives and turns.

Very good eye, there, Steve. I missed that detail but believe you're correct. Biggest issue I see with a truly flat pirouette type spin is the loss of lift from the wings as airspeed drops and reverses, especially across the wing that is pivoting backwards.

I don't know if think a true heli-style pirouette is very likely, but we know that conventional airframes can enter flat spins.

With appropriate flying technique, we should be able to unload Gs from the plane and kick it into a couple rotations at least before it drops into recovery.

Envision doing this with a glider, where the surfboard is the glider and the wave is the cliff face... very do-able, I think.

You guys are probably giving me credit for more lateral thought than I intend
The "Dorsal fin" was only a replacement for the lost vertical surface above the wing.
I would really like the wing to be a one piece removable item both for strength, weight and convenience.
It would also afford us the opportunity to test some different wing plan forms and sections.
I'll have to get to shaping the fuz to see what it looks like!

You guys are probably giving me credit for more lateral thought than I intend

Flat spin?
I've seen one of those Parkzone Strikers doing an inverted flat spin. It goes for as long as you like and does about 3 spins per second...(guess), like a "frisbee"
I beleive it prefers inverted to upright. OK!.......it has twin rudders and is a delta wing.

Just a question!
Do the wings need to generate lift in a spin?
How many spins is enough?